Buildings are often constructed with an expansion joint or other joint space between adjacent structures. Whether the space lies between adjacent buildings or adjacent portions of the same building, it is often desirable to install a fire barrier which acts to prevent fire from traveling along the space. The design of such fire barriers can be complicated by several factors, including a relatively large potential cycling range, which commonly results from seismic movement (e.g., ground tremblings and earthquakes), settling and other actions.
Presently known fire barrier insulation systems used in expansion joints generally comprise an insulation material having metal foil or other sheeted backing, and may additionally include a supporting screen. Examples of screen supported fire barriers are found in pending U.S. application Ser. No. 08/766,105.
There are several problems, however, with the known fire barrier insulation systems. For example, the known systems can be relatively bulky and difficult to roll, which in turn creates transportation and storage problems. In many instances the metal sheeting is corrugated across the insulation material to improve the rollability, as in U.S. Pat. Nos. 5,032,447 and 5,218,506, but corrugated sheeting is only "rollable" in sheet form. Thus, a material formed from corrugated sheeting and having a rectangular cross section will not be rollable if all four sides are formed from corrugated sheeting. Such materials become more rigid as their thickness increases.
Some fire barrier materials, such as that discussed in U.S. Pat. No. 5,304,408 (hereinafter "the '408 patent"), are rollable, but are not well suited for use in expansion joints. The material of the '408 patent comprises a heat resistant layer and an insulating layer encapsulated by two wire mesh sheets. One disadvantage of the material of the '408 patent is that it requires excessive use of the wire mesh all the way around the material even though the heat resistant layer itself might be adequate to hold the material together along one side. Another disadvantage is that the heat resistant layer must remain relatively thin for the material to remain rollable. Yet another disadvantage is that the material is extremely flexible, which, although good in situations which require the material to be wrapped around objects, decreases its suitability to act as an expansion joint.
Thus there is a continuing need to develop rollable fire-rated expansion joints.